Derivation and Validation of a Scoring System to Stratify Risk for Advanced Colorectal Neoplasia in Asymptomatic Adults: A Cross-sectional Study

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Patrick O. Monahan, PhD

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Timothy E. Stump, MA

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Elizabeth A. Glowinski, RN

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

David F. Ransohoff, MD

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

This article was published online first at www.annals.org on 11 August 2015.

From Indiana University School of Medicine, Regenstrief Institute, Indiana University Melvin and Bren Simon Cancer Center, Richard L. Roudebush Veterans Affairs Medical Center, and Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana, and University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Grant Support: By the National Cancer Institute (R01-CA104459); the Walther Cancer Institute, Indianapolis, Indiana; the Indiana University Melvin and Bren Simon Cancer Center; and a project development team within the Indiana Clinical and Translational Sciences Institute (grant UL1TR001108 from the National Center for Research Resources, National Institutes of Health), Indianapolis, Indiana.

Disclosures: Dr. Imperiale reports grants from the National Cancer Institute, the Walther Cancer Foundation, the Indiana Clinical and Translational Sciences Institute, and the Indiana University Melvin and Bren Simon Cancer Center during the conduct of the study. Authors not named here have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?ms Num=M14-1720.

Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer.

Abstract

Background:

Several methods are recommended equally strongly for colorectal cancer screening in average-risk persons. Risk stratification would enable tailoring of screening within this group, with less invasive tests (sigmoidoscopy or occult blood tests) for lower-risk persons and colonoscopy for higher-risk persons.

Objective:

To create a risk index for advanced neoplasia (colorectal cancer and adenomas or serrated polyps ≥1.0 cm, villous histology, or high-grade dysplasia) anywhere in the colorectum, using the most common risk factors for colorectal neoplasia.

Derivation and validation of a risk index based on points from regression coefficients for age, sex, waist circumference, cigarette smoking, and family history of colorectal cancer.

Results:

Among 2993 persons in the derivation set, prevalence of advanced neoplasia was 9.4%. Risks for advanced neoplasia in persons at very low, low, intermediate, and high risk were 1.92% (95% CI, 0.63% to 4.43%), 4.88% (CI, 3.79% to 6.18%), 9.93% (CI, 8.09% to 12.0%), and 24.9% (CI, 21.1% to 29.1%), respectively (P < 0.001). Sigmoidoscopy to the descending colon in the low-risk groups would have detected 51 of 70 (73% [CI, 61% to 83%]) advanced neoplasms. Among 1467 persons in the validation set, corresponding risks for advanced neoplasia were 1.65% (CI, 0.20% to 5.84%), 3.31% (CI, 2.08% to 4.97%), 10.9% (CI, 8.26% to 14.1%), and 22.3% (CI, 16.9% to 28.5%), respectively (P < 0.001). Sigmoidoscopy would have detected 21 of 24 (87.5% [CI, 68% to 97%]) advanced neoplasms.

Limitations:

Split-sample validation; results apply to first-time screening.

Conclusion:

This index stratifies risk for advanced neoplasia among average-risk persons by identifying lower-risk groups for which noncolonoscopy strategies may be effective and efficient and a higher-risk group for which colonoscopy may be preferred.